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Modelling inelastic behaviour of orthotropic metals in a unique alignment of deviatoric plane within the tress space

Mohd Nor , Mohd Khir (2016) Modelling inelastic behaviour of orthotropic metals in a unique alignment of deviatoric plane within the tress space. International Journal of Non-Linear Mechanics. ISSN 00207462


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A finite strain constitutive model to predict the deformation behaviour of orthotropic metals is developed in this paper. The important features of this constitutive model are the multiplicative decomposition of the deformation gradient and a new Mandel stress tensor combined with the new stress tensor decomposition generalized into deviatoric and spherical parts. The elastic free energy function and the yield function are defined within an invariant theory by means of the structural tensors. The Hill’s yield criterion is adopted to characterize plastic orthotropy, and the thermally micromechanical-based model, Mechanical Threshold Model (MTS) is used as a referential curve to control the yield surface expansion using an isotropic plastic hardening assumption. The model complexity is further extended by coupling the formulation with the shock equation of state (EOS). The proposed formulation is integrated in the isoclinic configuration and allows for a unique treatment for elastic and plastic anisotropy. The effects of elastic anisotropy are taken into account through the stress tensor decomposition and plastic anisotropy through yield surface defined in the generalized deviatoric plane perpendicular to the generalized pressure. The proposed formulation of this work is implemented into the Lawrence Livermore National Laboratory-DYNA3D code by the modification of several subroutines in the code. The capability of the new constitutive model to capture strain rate and temperature sensitivity is then validated. The final part of this process is a comparison of the results generated by the proposed constitutive model against the available experimental data from both the Plate Impact test and Taylor Cylinder Impact test. A good agreement between experimental and simulation is obtained in each test.

Item Type: Article
Uncontrolled Keywords: Constitutive formulation; elastoplasticity; orthotropic materials; finite strain deformation
Subjects: T Technology > T Technology (General)
Divisions: Faculty of Mechanical and Manufacturing Engineering > Department of Mechanical Engineering Technology
Depositing User: Mr. Mohammad Shaifulrip Ithnin
Date Deposited: 25 Apr 2017 07:52
Last Modified: 25 Apr 2017 07:52
URI: http://eprints.uthm.edu.my/id/eprint/8427
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